1. Field of the Invention
The invention concerns a closure for drinking bottles.
2. Description of Related Art
Closures for drinking bottles are known in many different kinds from the state of the art. For example, AT 509 897 describes a hand-screwed closure for drinking bottles, wherein the hand-screwed closure has a through hole in which a seal which can receive a drinking straw can be releasably fixed. AT 509 897 describes two openings in the closure cap which are intended to prevent the occurrence of reduced pressure in the drinking bottle during the drinking process. For that purpose, provided in a seal are venting slots, the positions of which, in the condition of being screwed to the bottle, must correspond to the venting openings. Accordingly, the seal has a positioning device so that the venting slots in the seal can be arranged in the correct positions with respect to the venting openings in the closure cap when the closure is screwed to the drinking bottle. Such venting slots are also not optimum from a hygiene point of view as they cannot be cleaned well.